Update Vignettes to use `.data[[]]`

[jwildfire]

Consider moving from:

plot_aes <- aes_(
   x=as.name(settings$studyday_col), 
   y=as.name(settings$value_col), 
   group=as.name(settings$id_col)
)

To:

plot_aes <- aes(
   x=.data[[settings$studyday_col]] 
   y=.data[[settings$value_col]] 
   group=.data[[settings$id_col]]
)

Also add a section discussing standard evaluation and providing some references like:

• https://mastering-shiny.org/action-tidy.html
• https://ggplot2.tidyverse.org/reference/aes_.html

[jwildfire]

cc: @xni7

[jwildfire]

Made updates in cookbook and chart config repos.